Core-drill head assembly



April 21, 1931- c. T. ALLEN CORE DRILL HEAD ASSEMBLY Filed Oct. 6, 1,928

flf frae 674551-53 ZHusn/ HrroEA/EY Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE CHESTER '1. ALLEN, OF VENTURA, CALIFORNIA, ASSIGNOR OF ONE-HALF TO FAY OLIVER, OF VENTURA, CALIFORNIA CORE-DRILL HEAD ASSEMBLY Application filed October 6, 1928. Serial No. 310,745.

This invention relates to core drills of the type commonly used in combination with rotary drilling equipment for the purpose of sampling the formation at various points during the construction of an oil well.

The invention embodies a head assembly adapted to be associated with that class of core drill known as the double barrel type in which a core cutting shoe is suspended from the lower end of an outer barrel which in turn is supported by means of a drill string and in which an inner barrel is enclosed within the outer barrel and is supported by the upper end of the cutting shoe in a manner such that it will receive a core which is cut from the formation by the shoe.

Circulating fluid in the form of water or mud, is ordinarily pumped through the drill string into an annular passage formed between the outer and inner barrel from which it passes to the cutting shoe where it is directed against the cutting blades in various manners, depending upon the construction of the shoe.

One of the primary difliculties ordinarily encountered in the use of such a barrel resides in the prevention of the circulating fluid from entering the inner core receiving barrel. Various types of construction have been devised for the purpose of directing the circulating fluid away from the top of the inner barrel and downward between the two barrels. The most common constructions used for this purpose employ various forms of valves which are mounted directly in the upper end of the inner barrel or in especially constructed fittings supported thereon. Although the mentioned valves are effective, to a greater or lesser extent, in preventing circulating fluid from entering the inner barrel, it is obvious that the advance of the core upward through the inner barrel must act against the pressure of the circulating fluid which tends to force the valve down upon its seat. If pieces of sediment or cuttings carried in the circulating liquid lodge beneath the valve, the fluid is diverted from its regular course into the inner barrel and tends to wash the core out of the barrel.

It is an obj eet of this invention therefore to produce a head assembly adapted for use in core drills in the class described in which the use of valves is eliminated.

It is a further object of the invention to produce a head assembly in which the upward circulation of the fluid about the outer barrel has an aspirating effect upon the upper inner end of the core receiving barrel which will assist in drawing the fluid from above the core and consequently decrease the pressure upon the upper end of the core.

It is a still further object of the invention to produce a device of the character described which may be easily and economically constructed and readily assembled.

Other objects and advantageous features in the construction of this invention will be better understood from the following description of the accompanying drawings which are chosen for illustrative purposes only and in which Figure 1 is an elevational view partly in section showing a core drill embodying this invention.

Figure 2 is an enlarged sectional view illustrating the head assembly of the core barrel shown in Figure 1.

Figure 3 is a sectional plan viewtaken substantially in the plane represented by the line 33 in Figure 2.

Figure 4 is a plan view taken substantially in a plane represented by line 44 in Figure 2.

More particularly describing the invention asherein illustrated, reference numeral 11 indicates a core drill embodying a core cutting shoe 12 and an outer barrel 13 which is supported from the lower end of a drill string 14:.

An inner barrel 15, enclosed within the outer barrel 13 is supported in the shoe 12 in any standard manner. The inner barrel 15 is adapted to receive a substantially tubular head 16 which extends upwardly from the upper end thereof. The upper end of the head 16 is provided with a shoulder 17 above which a packing ring 18 is mounted, and the packing ring 18 is held in firm engagement with the shoulder 17 by means of a tubular collar 19 whichis in threaded engagement with the top of the tubular head 16.

A hollow body member, which for the purpose of description is termed a partitionin member, is indicated by reference numera 20 and is illustrated as being supported in threaded engagement with the upper interior surface of the outer barrel 13.

This partition member 20 is provided with what may be termed a partition head 21, through which circulating passages 22 extend in the manner illustrated.

The lower portion of the'hollow body or partition member 21 is provided with an upwardly extendin recess or hollow section 23 which is adapte to receive the upwardly extending head 16 mounted on the upper end of the barrel.

A tubular member in the form of a nipple 24 is mounted in the upper end of the hollow section 23 and extends outwardly through the outer barrel 16 as illustrated in Figures 1 and 2.

It will be understood from the illustration in Figure 2 that fluid passing from the inner barrel will be directed through the head member 16 into the hollow section 23 and will flow therefrom through passage 24 to the exterior of the outer barrel 13, such passage bein directly through the side wall of the outeriarrel.

The circulation fluid which is pumped into the well through the shoe 12 passes upward and about the outer barrel, and in traveling past aperture 25 produces an aspirating effeet in the tubular member 24 which acts to draw the liquid from the inner barrel to the outer surface of the outer barrel.

In assembling a core barrel embodying the invention, the first operation is preferably the insertion of the hollow body member or partitioning member 16 into the outer barrel 20. This member is advanced into the core barrel to a point at which the apertures which receive the nipple 24 are concentric. The nipple 24 is then screwed into the threaded aperture in the inner core barrel,

after which it may be welded, brazed or otherwise secured in the outer barrel. The inner core barrel 15, carrying the tubular head 16, is then inserted from the bottom of the outer barrel and the entrance of the head 16 into the hollow section 23 is facilitated-by the provision of an annular beveled inner surface on the lower edge of section 23.

The packing member 18 provides a liquid tight fit between the tubular head and the hollow section and the head 16 and section 23. are preferably made of such length as to within its sco e such changes as may fairly come within t e spirit of the appended claim.

I claim as my invention:

A core drill, embodying: an outer barrel havin internal screw threads at the upper end t ereof; an inner barrel; a partltion member screw-threadedly mounted in said threads in said outer barrel, said partition member comprisin a downwardly extending chamber open at the lower end and a partition head above said chamber with passages therethrough, exterior of said chamber; a tubular head mounted on the upper end of said inner barrel and adapted to fit within said chamber; 'an external packing ring on said tubular head arranged to fit within said chamber; and a tubular member arranged below said partition head forming a passage from the interior of said chamber above sa1d tubular head to the exterior of said outer barrel.

In testimony whereof, I have hereunto set my hand at Ventura, California, this 24th day of September, 1928.

CHESTER T. ALLEN.

render the head assembly adaptable to core barrel constructions of various lengths.

It will be understood that, while I have herein described and illustrated one embodiment of the invention, it is not limited to the precise construction set forth but includes 

